Just last year I delivered to a warehouse, got my signature and left. I get a message later telling that I need to go back and deliver their daily NDA package. I told them I did. I separate all my warehouse deliveries for people if I can. Stack like boxes together and such but always separate my NDA into another pile. Customer says, no I didn't, it's not there. I told them, "tell them to check under the dock plate, it may have slipped down between the plate and the floor." Sure enough, that where it was. So between me and the customer, one of us put it up there and it disappeared. But of course, it was completely my fault according to the customer.